Elevators of moderate speed, typically used in medium height buildings, are conventionally geared machines. The ripple in torque which may be created by leakage currents in the motor is fairly well damped out by the effect of the gears, which not only reduce the physical effect on the cab through the gear ratio, but also have a significant damping effect. However, the same is not true in higher speed gearless machines. It has been found that the leakage currents resulting from inevitable ground capacitance of each of the phases of a multi-phase motor driven by a fast switching frequency inverter introduce errors into the measurement of current of each phase, which is used to control the motor drive. This systematic current error can cause torque ripple at low, mechanically-relevant frequencies, thus leading to considerable elevator vibration.